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Visual Basic Combo API SendMessage: Instantly Fill a Combo with Files, Folders or Drives |
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Posted: | Friday May 14, 1999 | |
Updated: | Monday December 26, 2011 | |
Applies to: | VB4-32, VB5, VB6 | |
Developed with: | VB6, Windows 98 | |
OS restrictions: | None | |
Author: | VBnet - Randy Birch | |
Related: |
SendMessage: Instantly Fill a List with Files, Folders or Drives | |
Prerequisites |
None. |
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This
routine demonstrates using SendMessage to populate a combo box with any combination of files, directories and drives. Although this
demo uses the wildcard *.*, the method is valid for any mask.
Note that the constant value for 'READWRITE' is 0, the same as the vb constant 'Archive'. In VB you can not mask out the archive files to only return hidden files (for example). But by using the API value DDL_EXCLUSIVE Or'd with the type to be listed, you end up with the needed control over the display of files. The added bonus is that this method is that it's instantaneous. |
BAS Module Code |
None. |
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Form Code |
Create a form containing six command buttons in a control array (Command1(0) - Command1(5)), a label (Label1) and a combo (Combo1). Add the following code to the form: |
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Option Explicit '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' Copyright ©1996-2011 VBnet/Randy Birch, All Rights Reserved. ' Some pages may also contain other copyrights by the author. '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' ' Distribution: You can freely use this code in your own ' applications, but you may not reproduce ' or publish this code on any web site, ' online service, or distribute as source ' on any media without express permission. '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' Private Declare Function SendMessage Lib "user32" _ Alias "SendMessageA" _ (ByVal hwnd As Long, _ ByVal wMsg As Long, _ ByVal wParam As Long, _ lParam As Any) As Long Private Const CB_DIR = &H145 Private Const CB_RESETCONTENT = &H14B Private Const DDL_READWRITE = &H0 Private Const DDL_READONLY = &H1 Private Const DDL_HIDDEN = &H2 Private Const DDL_SYSTEM = &H4 Private Const DDL_DIRECTORY = &H10 Private Const DDL_ARCHIVE = &H20 Private Const DDL_DRIVES = &H4000 Private Const DDL_EXCLUSIVE = &H8000& Private Const DDL_POSTMSGS = &H2000 Private Const DDL_FLAGS = DDL_ARCHIVE Or DDL_DIRECTORY Private Sub Form_Load() Command1(0).Caption = "normal files" Command1(1).Caption = "normal files and folders" Command1(2).Caption = "hidden files" Command1(3).Caption = "system files" Command1(4).Caption = "folders" Command1(5).Caption = "drives" End Sub Private Sub Command1_Click(Index As Integer) Dim numfound As Long Dim DDL_FLAGS As Long Dim searchPath As String searchPath = "c:\winnt\*.*" Select Case Index Case 0: DDL_FLAGS = DDL_EXCLUSIVE Or DDL_ARCHIVE Case 1: DDL_FLAGS = DDL_EXCLUSIVE Or DDL_ARCHIVE Or DDL_DIRECTORY Case 2: DDL_FLAGS = DDL_EXCLUSIVE Or DDL_HIDDEN Case 3: DDL_FLAGS = DDL_EXCLUSIVE Or DDL_SYSTEM Case 4: DDL_FLAGS = DDL_EXCLUSIVE Or DDL_DIRECTORY Case 5: DDL_FLAGS = DDL_EXCLUSIVE Or DDL_DRIVES Case Else End Select 'clear and populate the combo Call SendMessage(Combo1.hwnd, CB_RESETCONTENT, 0&, ByVal 0&) numfound = SendMessage(Combo1.hwnd, CB_DIR, DDL_FLAGS, ByVal searchPath) Label1.Caption = numfound + 1 & " " & Command1(Index).Caption & " found." End Sub |
Comments |
By changing the value of the DDL_FLAGS parameter to include or exclude specific DDL_ constants, you determine the type of file structure to include. |
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Copyright ©1996-2011 VBnet and Randy Birch. All Rights Reserved. |